Objective　To investigate the respiratory pathogens and clinical characteristics among children less than 6 years old and hospitalized with asthma exacerbation. Methods　From June 2009 to December 2016, 246 nasopharyngeal aspirate (NPA) from hospitalized children with acute asthma exacerbations were collected, and only one specimen was collected from each child; PCR and q-PCR were performed to detect respiratory syncytial virus (RSV), influenza virus (IFV), parainfluenza virus (PIV), human metapneumovirus (HMPV), coronavirus (CoV), human rhinovirus (HRV), adenovirus (ADV), human bocavirus (HBoV) and mycoplasma. Bacteria isolated at the same time. Results　162 males and 84 females were enrolled in the study, and the median age is 31 months (9-71 months); among them, there were 154 cases younger than 3 years old, and 92 cases aged 3-5 years old; 189 cases were mild asthma exacerbations, and 57 cases were severe asthma exacerbations. The number of hospitalized children with acute asthma in autumn is the highest. Among these 246 NPA specimens, 193 (78.5%) were positive for respiratory viruses, NPA culture was positive in 97 (39.4%), 16 (6.5%) were positive for Mycoplasma pneumoniae, but none was positive for Pneumonia chlamydia. The highest virus detection rate is RSV and HRV, moreover the detection rate of HRVC is significantly higher than other subtypes of HRV(P<0.05) ; HRV detection rate showed increased trend in spring and autumn (P>0.05); RSV has the highest detection rate in winter (P<0.05). Detection rate of human bocavirus and total respiratory virus was significantly increased in children younger than 3 years old; Detection rate of RSV is higher in children younger than 3 years than in children aged 3-5 years, while the difference was not statistically significant (P>0.05); there is no significant difference of HRV detection rate between different age groups (P>0.05). There is no difference in the detection of pathogens in children with mild and severe acute asthma exacerbations (P>0.05). The proportion of irregularly inhaled corticosteroids in hospitalized children with acute asthma exacerbations was 192(78.0%). Conclusions　The respiratory pathogens in hospitalized children with acute asthma exacerbations are mainly detected as viruses in our city. The detection of virus is decreased with ages. Respiratory virus infections  are important causes of acute asthma exacerbation in children younger than 6 years, and viral infections may be more important for acute asthma exacerbation in infants and young children.